City Plastics, UV Resistance

City Plastics UV Resistance

Some plastics are susceptible to attack from sunlight, in particular, the ultraviolet segment of the spectrum. When ultraviolet attack occurs the material may have a colour shift, become chalky on its surface, and crack or craze. There are a number of methods to reduce this problem. The addition of carbon black to the polymer will usually absorb most UV radiation. Chemical inhibitors are available for certain plastics, which improve the UV resistance. Paint and silicone coatings can also be used to completely cover exposed surfaces to sunlight (UV radiation). Additionally, there are several polymers on the market that are inherently UV resistant as well.

ABS
ABS is not suitable for outdoor applications because of its poor UV resistance. UV stabilized material can be manufactured, subject to minimum quantities of about 1000 kg.

Acetal
Standard grade acetal will degrade over time upon exposure to sunlight. The material can crack, become brittle, and develop a chalky appearance. Black sheet provides the best UV stability.

Acrylic
Acrylic is inherently one of the most UV stable materials available.

Nylon
Unpigmented nylon will degrade upon exposure to sunlight evidenced by discoloration and become brittle. Formulations containing carbon black particles provide the best UV stability.

PETG
Standard sheet is not UV stable. UV resistant sheet is available in some thicknesses.

Polycarbonate
Standard grade polycarbonate will degrade upon exposure to sunlight. Polycarbonate will yellow and become hazy after about 1 year of exposure. UV resistant grades are available. Mar Resistant grades are also UV stable.

Polyethylene
Unpigmented (natural) polyethylene will degrade upon exposure to sunlight evidenced by discoloration and become brittle. Black sheet provides the best UV stability.

Polypropylene
Standard sheet is not UV stable.

PTFE
Standard sheet is not UV stable.

PVC
Standard sheet is not UV stable, however it is better under UV than a lot of plastics. UV stabilised sheet is available.

Polystyrene (High Impact Polystyrene (HIPS))
HIPS is not suitable for outdoor applications because of its poor UV resistance. UV stabilized material can be manufactured, subject to minimum quantities of about 1000 kg.